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Patna, Bihar, India
Dr. Ajaya Kumar SinghDepartment of Chemistry (DST-FIST
Sponsored) Govt. V. Y. T. PG. Autonomous College, Chhattisgarh, India
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Lahore, Punjab, India
EDITORIAL BOARD MEMBERS
Ranganathan SubramanianDepartment of Chemistry, Indian Institute of
Technology, Patna, Bihar, India
Dr. Annapurna NowduriDepartment of Engineering Chemistry, A. U.
College of Engineering (Autonomous), Andhra University,Visakhapatnam, Andhra Pradesh,
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Puneet Mehrotra
Managing Director
1. Studies on the Kinetics of Thermal Decomposition of Copper Oxalate Mixed With Silver Oxalate K. Sarada, K. Muraleedharan 1
2. Kinetics and Mechanism of Ruthenium(III) Catalysed Oxidation of L-Arginine by Periodate in Alkaline MediumGarapati Sridevi, Nowduri Annapurna, Parvataneni Vani 12
3. Thermal Decomposition Kinetics of Mefenamic Acid CrystalsS. Ramukutty, E. Ramachandran 21
4. Kinetics vs. Thermodynamics: An OverviewVishal Jain 25
5. Graphene Modification for Thermal Modulators: A Current ReportSona Chahal 28
Contents
IJTCK (2016) 1–11 © JournalsPub 2016. All Rights Reserved Page 1
International Journal of Thermodynamics and Chemical Kinetics
Vol. 2: Issue 1
www.journalspub.com
Studies on the Kinetics of Thermal Decomposition of Copper
Oxalate Mixed With Silver Oxalate
K. Sarada, K. Muraleedharan* Department of Chemistry, University of Calicut, Calicut, India
Abstract
The coprecipitates, Ag2Cu(C2O4)nH2O of varying composition [Ag = (1 and 2)%], have been
synthesized and were characterized by means of IR, XRD, and SEM. The decomposition of
the prepared oxalates was monitored by differential scanning calorimetry (DSC) and
thermogravimetry (TG). The DSC studies reveal that the decompositions of the mixed
oxalates were all complex exothermic processes with resemblance to the exothermic reaction
of copper oxalate and ranges from 540 to 600 K. The decomposition kinetics was studied by
thermogravimetry at four different heating rates: 5, 10, 15, and 20 K/min. The TG data were
subjected to linear least squares analyses (in the range α = 0.1–0.9) using the
isoconversional methods of KAS, FWO, Vyazovkin, and Tang to find the values of activation
energy (Eα). The activation energies of the pure copper oxalate, in N2 atmosphere, obtained
by the above-mentioned methods are 192.1, 191.3, 191.9, and 192.3 kJ/mo1 and that of pure
silver oxalate are 179.5, 187.4, 187.9, and 179.9 kJ/mo1, respectively. Copper oxalate
coprecipitated with 1% silver oxalate gave activation energy values 206.4, 215.8, 216.6, and
206.9 kJ/mo1 and the coprecipitated with 2% silver oxalate gave activation energy values
182.8, 192.3, 193.1, and 183.3 kJ/mo1. The kinetic analysis of copper–silver oxalates
prepared shows a decrease in average activation energy with increase in the concentration of
silver oxalate. The variation of activation energy during thermal decomposition reflects the
changing mechanism during the course of the reaction. It is observed that the activation
energy of copper oxalate is decreased from its original value by the addition of 2% Ag2C2O4.
Hence, it will be interesting to study further about the effect of addition of Ag2C2O4 higher
than 2%.
Keywords: decomposition kinetics, differential scanning calorimetry, isoconversional
methods, thermogravimetry
INTRODUCTION
Thermal decomposition of metal oxalates
is an important field of solid state
chemistry.[1–6]
Transition metal oxalates
act as precursors for the synthesis of oxide
nanoparticles that are involved in several
industrial and analytical applications.[1]
High purity transition metal oxalates can
be made by co-precipitation techniques, in
which the metal ions are simultaneously
precipitated in the expected stoichiometric
proportions and provide the possibility of
controlling the physical and chemical
properties of the final products. Most of
the single phase solid solution precipitates
assuring homogeneity. Though there is a
chance of segregation during precipitation,
the degree of mixing is far superior to that
obtained with conventional mixing
techniques. Oxalates form solid solutions
which can be easily decomposed. The
decomposition kinetics of many oxalates
IJTCK (2016) 12–20 © JournalsPub 2016. All Rights Reserved Page 12
International Journal of Thermodynamics and Chemical Kinetics Vol. 2: Issue 1
www.journalspub.com
Kinetics and Mechanism of Ruthenium(III) Catalysed Oxidation
of L-Arginine by Periodate in Alkaline Medium
Garapati Sridevi1, Nowduri Annapurna
2, Parvataneni Vani
3* 1AU College of Engineering for Women, Andhra University, Visakhapatnam, AP, India
2Department of Engineering Chemistry, AU College of Engineering (A), Andhra University, Visakhapatnam, AP, India
3Department of Inorganic and Analytical Chemistry, Andhra University, Visakhapatnam, AP, India
Abstract
The kinetics of the ruthenium(III) catalysed oxidation of L-arginine by periodate was studied
spectrophotometrically in alkaline medium at 280 nm and at a temperature 35 ± 0.1°C. It
was found that the reaction is first order with respect to [catalyst] and [periodate]. The
reaction showed fractional order dependence on [substrate] and [alkali]. The oxidation
product of the reaction was found to be aldehyde. The anionic species of arginine (Arg) is
considered to be the reactive species. A suitable mechanism involving complexation between
Arg
and [Ru(VIII)] was proposed leading to the rate law.
The activation parameters of the rate determining step Ea, and ∆S
#, were computed to be 57.3
± 1.9kJ mol1
and -196.5 ± 5.8 JK1
mol1
respectively.
Keywords: oxidation of L-arginine, periodate, ruthenium (III)
INTRODUCTION
Arginine is one of the essential amino
acid and is an important constituent of
proteins. Since it is an essential amino
acid it cannot be synthesized by human
body.
The kinetics and mechanism of
oxidation of arginine were studied
previously using various oxidants.[1–15]
In continuation of our studies on the
oxidation of arginine,[16,17]
we now
report the mechanism of its oxidation in
alkaline medium by periodate in
presence of ruthenium(III).
Ruthenium(III) acts as a catalyst in
several redox reactions in alkaline
solution. The trivalent state is the most
stable oxidation state for ruthenium. The
mechanism of the catalysis is quite
complicated due to the formation of
different intermediate complexes, free
radicals and different oxidation states of
ruthenium.
The uncatalysed oxidation of arginine
by alkaline periodate[17]
was studied at
323K. Since there is no direct reaction
between arginine and periodate at 308K
and since ruthenium(III) was found to
catalyse the reaction considerably, we
have under taken a detailed kinetic and
mechanistic study of the title reaction
in 0.4 mol dm3
alkaline medium.
Rate =dt
periodate][___________-d=
k K1 2K Arg[
t]
t[ ]Ru
IIIOH
-[ ]
____________________________
1K2K
tArg[ ]1 ++ +]Arg t
[ OH-[ ] K1K2 OH
-[ ]
IJTCK (2016) 21–24 © JournalsPub 2016. All Rights Reserved Page 21
International Journal of Thermodynamics and Chemical Kinetics Vol. 2: Issue 1
www.journalspub.com
Thermal Decomposition Kinetics of Mefenamic Acid Crystals
S. Ramukutty, E. Ramachandran*
Department of Physics, Thiruvalluvar College, Papanasam, India
Abstract
Single crystals of mefenamic acid were crystallized by gel growth method for the first time in
literature. Crystal structure was confirmed using single crystal X-ray diffraction analysis.
Kinetic analysis was made from the isothermal thermogravimetric analysis/differential
thermal analysis (TGA/DTA) data using Coats–Redfern (CR) relation. Thermodynamic
parameters were also determined. Arrhenius equation for mefenamic acid is k = 0.28 × 109
e–116551/RT
mol–1
s–1
.
Keywords: kinetic analysis, mefenamic acid, thermal analysis
INTRODUCTION
Kinetic analyses were carried out in
growth as well as decomposition of
crystalline materials. Among this thermal
analysis during thermal decomposition is
useful for the determination of rate of
chemical reaction, decomposition products
and thermodynamic parameters. In
pharmaceutics problems like the purity
level, qualitative and quantitative analysis
of drug formulations and polymorphism
are resolved using thermal analysis.[1,2]
Moreover, the shelf life period of the
drugs may be estimated by the kinetic
parameters. Further solid state kinetics
studies are helpful in the calculation of the
parameters of Arrhenius equation and to
determine the mechanism of
decomposition reaction.
Mefenamic acid [2-(2,3-
dimethylphenyl)aminobenzoic acid] is a
non-steroidal anti-inflammatory drug
(NSAID). It is used to decrease pain and
blood loss from menstrual periods.
Thermal analysis of pure mefenamic acid
was less reported. Thermal analyses of few
NSAIDs are reported by the authors.[3–6]
Presently, single crystals of mefenamic
acid were crystallized by gel growth
method. The crystal structure of the grown
crystal was confirmed using single crystal
X-ray diffraction method. Thermal
analysis was carried out using isothermal
thermal decomposition. Coats–Redfern
relation was applied on the thermal
decomposition data to evaluate the kinetic
parameters from the thermal analysis.
EXPERIMENTAL
Mefenamic acid was purchased from Blue
cross laboratories Ltd., Goa, India.
Organic solvents were purchased from
Spectrum Chemical Reagents, Cochin.
Test tubes were used as crystal growth
vessels. Crystal growth by reduction of
solubility was employed for the
crystallization. An aqueous solution of
sodium metasilicate (Na2SiO35H2O) of
specific gravity 1.06 gm/cm3 was prepared
and the pH of the solution was adjusted
using 5 M acetic acid. 5% w/v of
mefenamic acid in methanol solution was
placed over the set gel taken in the test
tube. Transparent, long rod shaped crystals
IJTCK (2016) 25–27 © JournalsPub 2016. All Rights Reserved Page 25
International Journal of Thermodynamics and Chemical Kinetics Vol. 2: Issue 1
www.journalspub.com
Kinetics vs. Thermodynamics: An Overview
Vishal Jain MM College, Modinagar, Uttar Pradesh, India
Abstract
Almost every chemical reaction has a kinetic and a thermodynamic aspect. The terms
‘kinetic’ and ‘thermodynamic’ though inter-related are two different facets of a chemical
reaction. Here is an overview of the underlying relationships between the two through
application to chemical reactions and an example from natural processes.
Keywords: activation energy, chemical reaction, kinetic, reactant, thermodynamics
Introduction
Chemical reactions are described as those
processes in which a set of molecules or
chemicals referred as ‘reactants’ are
changed into another set of new molecules
or chemicals called the ‘products’.
Kinetics and thermodynamics are two
inter-related yet different and important
aspects of such chemical reactions. Kinetic
study gives us the information about how
fast a reaction will run while
thermodynamic analysis answers the
question of whether a reaction is
thermodynamically favorable or not.
Kinetics Overview
Kinetic studies tell us how fast or slow a
reaction can occur. In other words, it helps
in determining the rate of a chemical
reaction. The quantity related to kinetics is
the rate constant ‘k’. This rate constant is
associated with the activation energy
required by the reactants to proceed the
reaction in forward direction. The rate
constant thus, measures how fast the
reaction reaches the equilibrium assuming
the reactants have sufficient activation
energy that pulls the reaction in forward
direction, i.e., from reactants to formation
of products.[1]
The rate of reaction, the rate
constant, and the kinetic energy required
for activation of reaction together indicates
how fast the reaction reaches equilibrium.
The value of ‘k’ can be increased in the
presence of a catalyst such as an enzyme.
This increases the rate of reaction. The
catalyst does this in two ways: first by
increasing the energy of reactants and
second by lowering the transition state
energy, shown in Figure 1.
IJTCK (2016) 28–29 © JournalsPub 2016. All Rights Reserved Page 28
International Journal of Thermodynamics and Chemical Kinetics Vol. 2: Issue 1
www.journalspub.com
Graphene Modification for Thermal Modulators: A Current
Report
Sona Chahal*
Department of Electrical and Electronics, Lord Krishna College of Engineering, Ghaziabad, Uttar Pradesh, India
Graphene has attracted a lot of interest in
recent years on account of its unique
electrical and optical properties. Graphene
has a spring constant in the range of 1-
5N/m and a Young's modulus of 0.5 Tpa,
which shows that it has a breaking strength
200 times greater than steel and one of the
strongest materials known. Moreover, the
electronic structure of graphene is unique
in the sense that it can absorb a significant
part of incident white light. From the point
of view of thermal properties, graphene
exhibits strong heat conductivity which
can be improved further by embedding
multiple layers of graphene into silicon
chips.
While designing electronic components,
generation of excess heat creates big
problem. Getting rid of the heat generated
is quite cumbersome. In a recent report,
researchers at Agency for Science,
Technology and Research (A*STAR),
Singapore, have found an alternative by
which the heat generated in graphene can
be modified and utilized in a more
efficient way.
Graphene is a carbon form consisting of
planar sheets which are one atom thick,
with the atoms arranged in a honeycomb-
shaped lattice, and has an extraordinarily
high thermal conductivity. Researchers
from the A*STAR Institute of High
Performance Computing have developed a
way to reduce graphene's thermal
conductivity, allowing excess heat to be
dissipated or utilized for generation of
electricity.
The team demonstrated that clamping a
graphene sheet between two other
graphene sheets under moderate pressure
will decrease the thermal conductivity by
approximately one-third. Adding more
clamps and adjusting the pressure allow
the heat-flow to be tuned, fashioning a
'thermal modulator', that is similar to
electrical components such as variable
resistors that control the flow of electricity.
The design is based on molecular
dynamics to simulate the movement of
phonons which are the thermal equivalent
of electromagnetism's photons. The
clamping does not cause any sort of
permanent damage to graphene.
The thermal properties of graphene can be
further modified by doping or introducing
some sort of defects in its structure that
will cause permanent change in the
material. The A*STAR team's approach,
however, provides a considerable
advantage, i.e., "It does not change the
crystal structure and is fully reversible-if
the pressure is removed, the graphene
returns to its pristine state".
It was observed that the boundaries of the
clamped area had the largest energy level
shift and showed maximum scattering. The
effect was less significant in center of the
clamps. The team then made efforts to
create more boundaries and so changed the
simulation from a single clamped area to
multiple smaller areas. It was found that
the thermal conductivity dropped
dramatically.
International Journal of
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Computer Science and Engineering « International Journal of Wireless Network Security« International Journal of Algorithms Design and Analysis« International Journal of Mobile Computing Devices« International Journal of Software Computing and Testing« International Journal of Data Structures and Algorithms
Nanotechnology« International Journal of Applied Nanotechnology« International Journal of Nanomaterials and Nanostructures« International Journals of Nanobiotechnology
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« International Journal of Renewable Energy and itsCommercialization
« International Journal of Environmental Chemistry« International Journal of Agrochemistry« International Journal of Prevention and Control of Industrial
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Civil Engineering« International Journal of Water Resources Engineering« International Journal of Concrete Technology« International Journal of Structural Engineering and Analysis« International Journal of Construction Engineering and
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Electrical Engineering« International Journal of Analog Integrated Circuits« International Journal of Automatic Control System« International Journal of Electrical Machines & Drives« International Journal of Electrical Communication
Engineering« International Journal of Integrated Electronics Systems and
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Material Sciences and Engineering « International Journal of Energetic Materials« International Journal of Bionics and Bio-Materials« International Journal of Ceramics and Ceramic Technology« International Journal of Bio-Materials and Biomedical
Engineering
Chemistry « International Journal of Photochemistry« International Journal of Analytical and Applied Chemistry« International Journal of Green Chemistry« International Journal of Chemical and Molecular
Engineering
« International Journal of Electro Mechanics andMechanical Behaviour
« International Journal of Machine Design andManufacturing
« International Journal of Mechanical Dynamicsand Analysis
« International Journal of Fracture and damageMechanics
« International Journal of Structural Mechanicsand Finite Elements
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Biotechnology « International Journal of Industrial Biotechnology and
Biomaterials« International Journal of Plant Biotechnology« International Journal of Molecular Biotechnology« International Journal of Biochemistry and Biomolecules« International Journal of Animal Biotechnology and
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Nursing « International Journal of Immunological Nursing« International Journal of Cardiovascular Nursing« International Journal of Neurological Nursing« International Journal of Orthopedic Nursing« International Journal of Oncological Nursing
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